Julia Menon (Preclinicaltrials.eu): “Registering your animal studies takes hardly any time and effort, and the benefits are huge”

In late 2026, Julia Menon will give a webinar at the PRBB to present Preclinicaltrials.eu, a platform to preregister research studies done with animals. This webinar will be part of the PRBB animal facility training plan, aimed at scientists conducting in vivo studies with mice, rats or zebrafish. 

The purpose of the webinar will be to present recent research data on the impact of preregistration, provide information regarding preregistration on Preclinicaltrials.eu, and offer a live demo of the platform. 

In advance of this webinar, we talk to Julia to learn more about the platform, how it works and why you should preregister your animal studies. 

Let’s start from the beginning. People tend to have a clear idea of what a clinical trial is, but what exactly are preclinical studies?  

A preclinical study is any study or experiment done with animals. I guess we could interpret that within ‘preclinical’ we could include studies with organoids, etc. For the time being we are not considering these in our platform, but my wish is that we will extend to these other models! 

Also to note, it’s not only about experiments that are testing a drug or intervention – as is the case with clinical trials -, although about 60% of the protocols we have are about that. But the rest are mechanistic, basic science experiments. And we even have some veterinary studies. 

And what does ‘preregistration’ mean? 

Preregistration means literally pre-specificying in advance what you will do and how you will do it.  

In our platform, it means submitting or publishing your protocol before you start experimenting. It means writing the hypothesis, expected outcomes, study design… basically what you are going to analyse and how you are going to do it.  

So, we are talking about a database of animal research studies protocols, with some projects that have not yet started, others that are ongoing, or others that are finished. 

That’s right. 

And what if after publishing the protocol, you decide to change something? 

That is perfectly normal; it is an acceptable part of research to deviate from your plan, as long as you are transparent and justify the deviations. In our platform, you are allowed to make changes to the protocol as many times as you need it in an easy and fast way, and each change is saved as a new version, so it is all traceable. 

Why is it important to preregister these studies?  

There are many reasons why preregistration is good: 

1. Quality reasons: First of all, it forces researchers to think exactly what they are going to do and how, so it increases best practices and robustness. And then, by making the protocol publicly available, other people can see it, check it, learn from it, see if there are any mistakes… It increases transparency and reproducibility overall. 

2. Ethical reasons: it avoids unwillingly repeating experiments others are doing, which reduces the number of animals used. 

3. Economic reasons: as above, avoiding unnecessary repetition saves money and reduces waste. 

4. Practical reasons: again, as a researcher it can be very helpful at the end of your project to look back to this planning and use it to report, to create a paper much quicker and in a way that is compliant with the ARRIVE reporting guidelines (the official recommendation checklist for the full and transparent reporting of research involving animals, which most journals request).  

5. Finally, it can lead to collaborations: if you see someone else doing something like what you were planning, you can contact them (we have an option on the website to do so) and explore potential partnerships. 

What other advantages has publishing the protocol in your platform? 

One very good characteristic of our platform is that you can also add a link to the paper once published, and also to the data/results (if they are in a repository already). So, in the case that you don’t manage to publish the results in a journal, at least the protocol and results are together in the same place. This reduces publication bias (the well-known phenomenon by which negative or unsuccessful results don’t get published) and ensures transparency. 

Also, having all that data there could potentially support meta research: systematic reviews, etc…  

That all sounds very good in theory, but is there any evidence of the real impact of preregistration? 

Recently there was this nice story of some authors who were expecting a big result for their project, and it turned out not very strong. They worried they would have a hard time publishing it, but the editor saw the study was preregistered and they said that influenced their decision to publish it. They saw it as proof of robustness, even if the results were not very significant. 

But beyond these anecdotal experiences, we have just published a preprint in which we looked at 55 papers, 22 had been preregistered (either with us or in the Animal Study Registry, another registration platform similar to ours based in Germany) and 33 had not. Those not preregistered were either published in the same journal or conducted by the same authors than the preregistered papers. When we did a blind analysis to check their quality, we found that preregistered papers scored higher quality than the controls according to the ARRIVE guidelines and also showed lower risk of bias (i.e. stronger internal validity). More importantly, preregistered papers published by the same team showed an improved reporting, emphasizing that these teams either improved and/or reported more completely thanks to their preregistration.

“A recent study we did showed that studies that had been preregistered had a better reporting, lower risk of bias and generally better quality”
Julia Menon

OK, I’m convinced. So if I’m a researcher and want to preregister my study, what do I do? 

You just create an account and fill a simple template with four parts: 

• One for general information about the project (title study, when it is starting and finishing, funding, etc), 

• The second one is the most important: it has the hypothesis, what outcomes you are looking for, how you are doing randomisation, what statistics you will use… The methodological details, enough information so that others can replicate if needed. 

• The third one has information about you (affiliation, where the study will take place). 

• And the fourth one is to ask whether you want to add an embargo, so the registration is hidden to third persons. 

It’s really quite simple. And the good thing is that this template is compliant with the ARRIVE reporting guidelines for studies with animals, which you have to follow when you publish your study. So, if you spend some time filling this form for the pre-registration, it will save you time later when writing up! 

Once you send it, we review it – not an ethical review, because that will already happen through the ethics committees – and not really a peer review, because we don’t have the time and expertise. Just an administrative check to see there’s enough detail, etc. 

And then we publish it! The researchers will then receive a couple of emails after the study planned end date  to check for any updates on their study, so they can either lift the embargo, or complete their registration with a link to the paper or the data, etc. 

Is the ethical approval compulsory before preregistering? 

The ethical review acceptance will have to happen at some point before doing the study, of course; but it is not compulsory for preregistration. However, we advise to preregister once you have the ethical acceptance, otherwise if the ethics committee asks for changes,  you will have to come and add those changes in our platform later, so it will be more work. 

Also, we can use the official ethical documents to populate our forms automatically, which saves a lot of time – althouhg only in 2 countries so far, France and the Netherlands. We are working on improving this system and doing it in other countries (we have accepted registrations from 36 countries, mostly European but also from elsewhere). Each country or even institution has its own format for the ethical approvals – often it’s similar content but organised in different ways, which makes automatisation more difficult. So what we are doing at the moment is we are creating guidelines for different institutes (we are currently looking for more institutes interested in doing it!) to map their standard ethical documents to our form and facilitate this transfer from the ethical documents to our forms. 

And if I’m a researcher that wants to see what studies are preregistered? 

Again, just create an account and search on the website! You can search by discipline, by species, etc. and use keywords. And if you see a project you are interested in, you have an option to contact the authors. Their identity is not disclosed, so they will know who you are but you won’t know who they are until they choose so. 

How many preregistered studies do you have on the platform? 

We have only 285. We’re still relatively new and small. You see, Preclinicaltrials.eu was created in 2018 and ran on a voluntary basis by a PhD student in Utrecht (The Netherlands). Her team had been thinking about the need for such a platform for a while, and when they saw there was nothing like that, they decided to create their own. It wasn’t until 2021 that they got some money from the government and could hire a couple of people to further support it.  

It’s surprising there aren’t more researchers using it – what are the drawbacks or challenges? 

Researchers often have concerns, although they can be lifted or reduced once they learn about how the platform works. For example: 

• Fear of scooping: researchers are worried that if they publish their protocol, other groups might be able to ‘copy’ it and do it faster. But we have an optional embargo period – of 1 year by default, but you can renew it for longer, or lift earlier if you’re done. During this period, your protocol is registered, but nobody can see it, so there’s no real danger of scooping. 

• Fear of too much admin burden and time wasted: researchers are already very busy, and this is an understandable concern. But it literally takes about 20-30 min to complete the whole process! And we are working on automatisation, so that if your institution/country has ethical approvals done through some platforms, we have a way to export some of the information (name of the study, methodology details etc.) directly, saving even more time. 

• Fear of retaliation by animal right activists: this is perhaps one of the major worries – if my name is here with a description of the study I will do, will I have activists targeting me? Again, very understandable. What we are doing to overcome this is that registration is anonymous; that is, you see the name of the institution where the experiments will take place, but not the name of the researchers. Of course, that has the downside that the researchers cannot receive attribution for their work. We’re trying to see if we can link it through ORCID so that researchers can be recognised for having done the registration. 

Do you think that it will or should become compulsory to pre-register animal studies? 

Yes! Really it takes hardly any time and effort, and the benefits are huge! Our goal is to collect enough support from different countries and then present it to the EU comission in  Brussels and ask for it to be put into legislation, at least for some animal research. I think it should start with the “late preclinical trials”, those done just before clinical trials, because they are the ones that require a higher number of animals and demand the highest quality to inform the clinic. But in the long run, if all exports are working and it’s easy to register, why not preregister all animal studies?